This invention relates generally to low temperature static seals and more particularly to a seal assembly having an elastomeric seal element wherein the assembly includes a pathway in the seal gland for enhancing fluid pressure communication with the seal element.
Static elastomeric seals, particularly those of the molded in place variety are very effective sealing devices. However, at sub zero temperatures, and more particularly in the range below -40.degree. F., the elastomer can become quite stiff. The geometry of the typical static seal is such that the groove, gland or confining retainer usually provides an intimate faying contact with the mating structure which may be a plate surface, flange face, cylindrical shell or the like. Therefore, it is often difficult for the contained fluid, which itself can be quite viscous at the low temperature, to flow through the extremely narrow gap between these mating surfaces and force the stiff elastomeric seal to move in vector-like fashion to effect the characteristic wedge-like sealing action.
Consequently, it is not unusual for the contained fluid to seep past the stiff, contracted seal crown interface with the mating surface, especially if pressure impulses are applied in cycles. This nuisance type seepage usually stops as the pressurized system warms up to a point where the elastomer regains its flexibility and expands sufficiently to reseat itself. This parameter is sometimes referred to as the TR-10 level of the compound.